It means stay with the rest of the group.
keep your chin up!
The meaning of the idiom suck it up is to stand up or stand tall amidst all troubles. It can also be reversed as "compose yourself", "bear your troubles", and "go on".
No. The word "idiom" is a noun. An idiom is a term or phrase whose meaning is different from the separate words in the term. For example, the idiom 'keep up' has little to do with keeping anything or with an upward direction. It means maintaining (keeping) one's relative position as it changes (goes up, i.e. increases in elapsed time or distance).
If you are exhausted but keep going anyway, you are running on empty.
Hang in there!
To keep struggling and not give up.
It means he's really angry.
It means "shut up" or "be quiet"
to come up with new ideas
It made me laugh very much.
It means to gather up enough courage to do something.
"To be" is not an idiom - it's a verb.